This invention relates to apparatus for fiberizing a moist sheet of pulp fibers into individual fibers, and while its utility is not so limited, the invention is particularly suited for the fiberization of cellulosic fibers which have been coated and/or internally impregnated with wet strength resins.
While numerous expedients have hitherto been proposed for fiberizing sheets of moist fibers into individual fibers, the effectiveness of such devices varies widely as does the quality of the fibers which are obtained. In particular, conventional mechanical fiberizing techniques tend to produce fiber damage - both length reduction and fibrillation - as well as knotting of the fibers.
The majority of the devices currently in use for fiberizing either wet or dry cellulose fibers are primarily dependent upon mechanical impact for fiber separation, which results in excessive fiber damage as well as knot formation. This is particularly true for wet cellulose fibers because of the tendency of the wet fibers to reform into knots. Efforts to reduce the knot content by reducing clearances or increasing retention times result in increased fiber damage.
It has also been proposed to fiberize cellulose pieces by feeding them through a tunnel containing one or more sets of fan blades and recirculating the fibers for as many passes as are required to effect the desired fiberization. Such arrangement has a cyclone-like effect and is inherently knot producing; and at the velocities involved, considerable fiber damage also can occur.
In contrast to the foregoing, the present invention provides a fiberization device uniquely capable of achieving in excess of 99% complete fiber separation without excessive damage to the fibers.